Triple digit heat could make Montana wildfires grow

National Weather Service forecasters said Tuesday that near-record temperatures and wind gusts up to 50 miles per hour this week could lead to explosive growth on wildfires that crews are battling across Montana.

Temperatures approached the triple digits in parched areas of eastern Montana Tuesday, where crews were battling a fire east of Roundup that already had scorched 63 square miles. More than 400 personnel are working the blaze, known as the Delphia Fire.

A red flag warning for critical fire conditions was in effect for most of Montana, western North Dakota and northwestern South Dakota through Wednesday. Forecasters cautioned against any activities that might produce sparks, warning that new fires could quickly take hold and existing fires could expand.

A cold front is expected to descend on the state by Thursday behind the gusting winds.

The Delphia Fire was reported 60 percent contained, but authorities warned it could break through hastily-constructed fire lines if those winds are as strong as forecast.

"With the winds that are predicted and the single digit humidity, it could easily cross those lines," said Gregg DeNitto with the U.S. Forest Service. "And if it hits more fuels, there's an extremely strong chance we could have a new fire start."

Gusts of up to 20 miles per hour were expected Tuesday on the fire and gusts of up to 40 miles per hour Wednesday, DeNitto said.

An estimated 80 homes in rural areas of Musselshell County are threatened by the fire. Officials said 15 to 20 outbuildings have burned.

North of Lincoln, the 12-acre Stonewall Fire near Lincoln was threatening a Forest Service lookout station. That fire was sparked Monday by an afternoon lightning strike.

More lightning strikes were reported in the Lincoln area overnight Monday. Fire spokeswoman Kathy Bushnell said none had materialized into fires as of Tuesday afternoon, but added that lightning-caused fires can sometimes smolder for days before they grow significantly.

Three other large fires in western Montana -- near the towns of Drummond, Condon and Ovando -- have scorched a combined four square miles. Crews were reporting some containment on each fire Tuesday.